The present invention relates to pattern control systems for circular knitting machines and in particular to a method and apparatus for the improved reading of the patterning memory therefor, in correspondence to the needle and course passage.
Conventionally constructed circular knitting machines of both the one and two cylinder type have in recent years been provided with "electronic" patterning control systems. Briefly in such machines, the needles are selectively movable between a rest or inoperative position and between a knitting position by operation of a selector jack, spring or clavette in response to a pulse input on a solenoid or similar electromagnetic mechanism. The signal or pulse is derived from a pattern control device having a memory, such as tape, punch card, or core matrix, in which the overall knitting pattern is stored and circuit, computer and logic means to correlate the pattern relative to each needle at each course and wale loop intersection.
Reference can be made for general information regarding several systems to the publication Electronics in Knitting, Charles Reichman, ed. Am. Soc. of Knitting Technologists and The National Knitted Outerwear Assoc. 1972, and for more specific information to the copending applications
Ser. No. 342,941, filed Mar. 20, 1973 pending. PA1 Ser. No. 246,623, filed Apr. 24, 1972 now abandoned. PA1 Ser. No. 246,792, filed Apr. 24, 1972 and now abandoned. PA1 Ser. No. 246,791, filed Apr. 24, 1972 now U.S. Pat. No. 3,874,198 PA1 Ser. No. 246,699, filed Apr. 24, 1972 and now abandoned.
In small diameter knitting machines equipped with electronic patterning systems it is customary to employ a memory having a smaller finite capacity (i.e. storage bits, memory cores, logic terminals) than the number of needles in the cylinder of the knitting machine and the number of patterned courses in the finished knitwork. This is possible, since the patterns used are of small overall extent and may be repeated several times about the circumference and along the length of the knitwork. Such systems are equipped with shift and/or reversible registers which determine or read the address, (i.e. the position, in terms of course and wale of the knitwork) of the patterning memory. Such registers have an adjustable length computing cycle so as to also enable the reduction enlargement of the dimensions of the design of the pattern and are reversible for the purpose of enabling the knitting of mirror-image designs.
A disadvantage of employing registers for the reading of the memory lies in the fact that regular shift of the register predetermines the reading of both the wale and the course of the memory pattern to a system of successive reading. Thus all of the various possibilities inherent in the capacity of the memory of the associated computer can not be utilized. Furthermore, should one pattern memory be employed to control a plurality of knitting machines, then each machine must be provided with reversible shift registers each having an individually adjustable computing length. As a result the systems employing shift registers are relatively complicated and expensive.
It is an object of the present invention to provide an improved method and apparatus for reading patterning memories for knitting machines in which the cost and complexity of the systems is greatly reduced.
These objects, as well as other objects and advantages of the present invention will be apparent from the following disclosure.